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  #1  
Old 10-17-2017, 09:42 AM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,296
Default autopilot update

Yesterday I got both new servos mounted and went through the ground tests.
Christer, at Stein air, tried to talk me through the trim set up but as usual I got lost at step two! Anyways.. A Cirrus owner friend of mine went for a ride with me this morning. The autopilot interface is identical to the Cirrus and he was able to run through the various scenarios. First off I had the automatic trim disabled. Everything worked well except the manual pitch trim action of the 14 is very sensitive above 150 knots and this was causing some issues in climbs and descents with the autopilot. I enabled the auto trim feature and it solved the pitch issues beautifully but in turns things when bad pretty quickly. One thing I retained from my discussion with Christer yesterday was that sometime the auto trim might be backwards even though the manual trim worked correctly. Another adjustment to reverse the auto trim setting and voila! everything works perfectly.
The HDG and NAV features work independently or together if required. The VNAV also works if you set it up a ways out from your destination. For example, if you want to descend to circuit height 3nm out of your destination you simple set your rate of descent, circuit height, rate of descent and away and at a computer derived distance from the airport a descent will automatically start and place you where you want to be. Awesome. Forgive me if I have used some incorrect terms.
Tomorrow my wife and I are heading out on a cross country flight into the US south west and I am very much looking forward to exploring the country in this awesome new aircraft.
I took the following picture this morning over my local airport, CYQS. You can see the reflection of the garmin screen in the windscreen.

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EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger under construction #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #2  
Old 10-17-2017, 12:09 PM
azflyer21 azflyer21 is offline
 
Join Date: Nov 2016
Location: Scottsdale AZ
Posts: 22
Default

Tom,
Are you using all Garmin products for the AP?
Also, if you head to AZ on your SouthWest trip, there is the Copperstate Fly-in 27-28 https://www.copperstate.org/ I would love to see your plane.

Kevin
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  #3  
Old 10-17-2017, 03:56 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,296
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Yes, pretty much everything is garmin and we will give it the cross country test. Copperstate looks interesting, I have never been. The weather will dictate our travels.
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger under construction #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #4  
Old 10-17-2017, 04:15 PM
Ivan Kristensen's Avatar
Ivan Kristensen Ivan Kristensen is offline
 
Join Date: Mar 2008
Location: Guelph Ontario
Posts: 163
Default South West trip

Tom,
Glad to hear you got your A/P issues sorted out. Here is wishing you and your wife a super good trip to Arizona, I will look forward to hearing all about is upon your return. Post some pictures!
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  #5  
Old 10-18-2017, 02:05 AM
gen1313 gen1313 is offline
 
Join Date: Sep 2014
Location: Forbes, NSW, Australia
Posts: 35
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Quote:
Originally Posted by Tom Martin View Post
Yes, pretty much everything is garmin and we will give it the cross country test. Copperstate looks interesting, I have never been. The weather will dictate our travels.
Hi Tom, I love the Garmin setup in my 14 but I am still finding new features. If you look in the setup menu (can't remember where) you will find that you can set the manual trim to different sensitivity at different speed. As you noted it is way too sensitive at high speed as installed.
I found out the hard way that I had my auto trim configured in reverse. When you engage the AP for a climb the trim acts in reverse and keeps hunting the wrong way for a setting that will give the correct climb. A nervous few seconds
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  #6  
Old 10-18-2017, 05:47 AM
g3xpert's Avatar
g3xpert g3xpert is offline
 
Join Date: Sep 2010
Location: Olathe, KS
Posts: 1,699
Post Garmin Autopilot Auto-Trim Setup

Hello,

We have posted this guidance in a couple of threads, but it probably bears repeating given the comments above about reversed trim motors.

First, a description of the trim system architecture. There are three ways that trim operates.

Servos Powered Down (backup trim mode)
In this dirt simple backup mode a relay closes inside the GSA 28 servo and passes the trim motor wires directly through the servo. The wires connected to input pins 11,12 at the servo are directly connected to output pins 13,14.
Servos Powered Up, Autopilot Disengaged
This is the normal mode of operation when the autopilot is disengaged. The trim control inputs on pins 11,12 of the servo are read by the servo microprocessor, and speed scheduling is added by the servo to automatically drive the trim motor and vary the speed of the trim motor (using Pulse Width Modulation) to match the speed scheduling configuration. Speed scheduling lets the GSA 28 servo run the trim motor fast at low airspeeds to quickly re-trim the aircraft and very slow at high airspeeds when small trim adjustments are needed.
Servos Powered Up, Autopilot Engaged
This is the normal mode of operation when the autopilot is engaged. It is very similar to the previous mode except that the servo ignores the inputs and drives the trim motor based on out-of-trim torque sensing that it does on its own.
Here is a simplified version of the steps explained in the G3X Installation Manual to configure/test your trim installation.
  1. Power off the servos.
  2. Use aircraft trim switches to run the trim motor. If the trim motor runs in the wrong direction, swap the trim motor wires at the control stick, at the servo on pins 11,12 (switch inputs), at the servo on pins 13,14 (trim motor drive wires), or at the trim motor itself.
  3. Verify that the trim now runs in the correct direction with the servos powered off.
  4. Apply power to the servos.
  5. Use the on screen controls on the servo configuration page to drive the trim motor for that servo.
  6. If trim motor runs in the wrong direction, change the trim motor direction setting on that page from Normal to Reverse (or Reverse to Normal if it is presently Reversed).
  7. Re-verify that the trim operates correctly in both the servo powered on and servo powered off conditions.

Let us know if you have questions.

Thanks,
Steve
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  #7  
Old 10-18-2017, 05:47 AM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,296
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Graham, thanks for that information. Is it in the configuration page or can it be done in the inflight autopilot setup?
This would be a welcome feature.
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger under construction #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #8  
Old 10-18-2017, 08:59 AM
TS Flightlines TS Flightlines is offline
 
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 1,897
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Awesome Tom----
have a safe trip!
Tom
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  #9  
Old 10-18-2017, 09:43 AM
BigD BigD is offline
 
Join Date: Jul 2012
Location: MS
Posts: 289
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Trim configuration starts at 34.4.11 on page 34-100 in the installation manual (Rev AC). it is in the configuration mode vs the 'regular' menu.

==dave==
N102FM
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  #10  
Old 10-18-2017, 04:50 PM
gen1313 gen1313 is offline
 
Join Date: Sep 2014
Location: Forbes, NSW, Australia
Posts: 35
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Quote:
Originally Posted by BigD View Post
Trim configuration starts at 34.4.11 on page 34-100 in the installation manual (Rev AC). it is in the configuration mode vs the 'regular' menu.

==dave==
N102FM
Thanks Dave for answering that. It's been a while since I set mine and I couldn't remember.
Vans have guidelines for this in the Service Info area under "G3X Autopilot/Trim settings".
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